book reviews a desirable degree of relevance and diver-
sity in chemical edncation, probably some students ~hauldbe encouraged to cnltivate a competence in those hard-earned of classical physical chemistry that are pertieularly useful in biology, geology, metallurgy, and industry, and that are highly relevant to the human condition in a culture seemingly committed to life-styles that demand ever more ~ollution-~roducing de-~ .energv-converting vices. I n addition to a relatively thorough introduction to the activity function, Rock's book is noteworthy for its wealth of solved problems, its introduction a t numerous places of "other variables," and, generally, its overall clarity. The book contains a dozen or more problems (without answers) a t the end of each one of its thirteen chapters, a table of thermodynamic data for some seventy familiar chemicals, and a concluding, compact, one-chapter survey of the high points of statistical thermodynamics. There are scarcely any typographical errors. Nearly every chapter has an excellent set of references, which do not seem to have been included merely to lend an air of artistic verisimilitude to an otherwise ~ e r h a p sbald and unconvincing narrative. Their inflnence on the text is immediately evident. I n goad measure, Rock's hook may be described as a judicious selection and thoughtful synthesis of material from those well-known classics on pare and applied. thermodynamics by Bridgman, Goggenheim, Rossini, Giauque, Latimer, Denbigh, Klots, Findlsy, Keesom, Hildebrsnd and Scott, Flory, Robinson and Stokes, Hamed and Owen, and particularly (the euthar acknowledges) Lewis and Randall (revised by Piteer and Brewer) and Zemsnsky. If you like the style and contents of these works, you and your students will prohilhly enjoy R ~ c k ' sgenerally well-executed introduction to chemical thermodynamics. The book's chief weaknesses, in my view, are these: a. relatively high density of desk-type problems in the eady chapters; an absence of solutions or comments (or w e n just answers) to the more provocative problems; several unnecessarily long derivations (for example, two pages and fourteen lines of equations to show that, given t,he Second Law in the form A S L . ~ 2 0, "the work done by asyst,em on passing from one state to another is a maximum when the change in state is carried out reversibly"); derivations that begin with no explanilt,ion of where one is headed and conclude with a statement telling, not showing, us that the result is important; an abbreviated, abstract, lightly motivated, Ceratheodory-like introduction of theentropy function; severel "evidently"~ [in no instance that I noticed is the succeeding st,stement "evident"; in rtt least one instance (eqn. 9.19) the succeeding statement is wrong (cf. eqn. (9.21))I; considerable (I feel aver-) emphasis on the heat capacity function (being replaced by HT - H S B ~on ) , t,he Gibbs-Dohem relation (not, I feel, "one of the most useful equstions in chemical thermodynamics"), on
A392
/
Journal of Chemical Education
the Phase Rule (Gibbs' chief contribution, in this regard, was the introduction of a new m e c p t , "phase"; computing a system's number of degrees of freedom is relatively simple, aee one knows how many components there are) and, generally, on strictly intramural thermodynamic relations (featured on the cover and frontispiece in a "Thermodynamic Square") and diddling around with partial derivatives. There are, also, several disconcerting lapses in logical consistency. At no point, for example, is it shown that (under certain conditions) a. system's Gihhs energy tends toward an extrenum. On the whole, however, this is a commendable effort. The treatment is thorough yet readable, up to the last chapter. Nowhere does the author get hogged down in unrewarding details. The overall halsnce is good. The worked-out examples are excellent. For many undergraduate chemistry majors, Rock's hook may be the best, serious introduction to classical solution thermodynitmics and the thermodynamics of electrochemical cells available.
Understanding Chemical Thermodynamics
George C . Pimentel, University of California, Berkeley, and Richard D. Sprdley, University of British Colnmbia, Canada. Holden-Day, Inc., Sltn Frmcisco, 1960. 219 pp. Figs. and tables. 15.5 X 23.5 cm. Hardbound, 86.50; softbound, $3.95. This is an unusual monograph and, on the whole, I think a good one. I t is intended far students in general ohemistry who will not necesserily continue in the physical sciences. I t contains scarcely half-8-doaen integral signs and no derivatives of any kind. The style is highly informal. Liberal use is made of andogieu, colloquialisms, italics, question marks, and exclamation points. One rather expects the authors to step forth fmm the printed page in sports shirt,s and sandals, any moment. The illustrations match the text. Weights don't just fell. Cars roll down landscaped hills in suburbia accompanied by little birds. Throughout, the book is a. lively introduction to n. Gurney-like blend of classical and ststistical thermodynamics embroidered by such remarks as "molecular mentality," "a fiction about friotion," and "when two NO1 molecules join together in the holy state of chemical bondedness, the loss of freedom of movement is considerable!' The monograph is noteworthy, also, for unusually detailed, pedagogically directed discussions of thermachemistry, the kinetics and thermodynamics of the HrIa reaction, and the reversible and irreversible expansion and compression of an ideal gas and the charge and discharge of an electrochemical cell.
The monograph concludes with an interesting section on bioenergetics (7 pages) and s useful appendix of thermodynamic data (I0 pages). I t contains, however, no problems, exercises, or questions. Many teachers and students of cbemistry-not least of all, perhaps, those teaching and taking advanced-plaoementlike courses in high schools-will probably enjoy this highly original monograph. For some students it may he the best introduction to thermodynemics ilveilable. I t will probably be read by many students. I hope so. Yet i t is seriously deficient in several respects. Its chief theorem is wrong, its principal derivation contains several misleading statements, its fund* mental conception fails to highlight-indeed, even to mention-the key relation of thermodynamics, and its general view of science is internally inconsistent. One may talk a t length about internal energy sod entropy. The key to under-
the absolute temperature: T = @ElM ) v . By page 122, many readers of Pimentel and Spratley may feel ressonably comfortable with E and S . And nearly every reader will know something about temperature: that it is an index of thermal behavior. Curiously, this fundsmental property of T is not mentioned by the ~uthors. Instead, following a, comperison of the thermal dissocistions of N.H4, NsF,, and NIO~,they state that "as temperature rises, the energy randomness becomes less and less important compared with positional randomness. . . . I n fact (emphasis added), AHIT is a measure of the energy randomness introduced by the heat of 8. reaction." Unfortnnately, "to make all this quantitative," there follows "a, rather laborious, hut revealing derivation" that, after 28 pages, culminates in this un-Berkeley-like statement, set in h d d type (p. 119): "After any spontaneous process, work must he converted to heat in order to restore the system to its initial state!' Now the explosion of hydrogen and oxygen in a bomb, forming liquid water, is a spontaneous process. Still, in restoring this chemical system to its init,ial state, it is possible to diminish, somewhat, the energy of its thermal surroundings. Pimentel snd Spratley's theorem is correct only if, in the initial, spontaneous process, the entropy of the chemical system increases. Pmfessional thermodynamicists will wince, also, at the casual way in which the mold Gibbs energy is introduced (pp. 137-8: "If both energy and entropy are extemive, their sum must also be extensive, so free energy is an extensive property. [But G is not even defined for systems not in internal thermal and hydmstatic equilibrium.] This means we can calculate the free energy of a gas mizture [emphasis added] as the w m of the free energies of its constituents.. ." [Not so. Generally, only the mass of a chemical system can he so treated.]); a t the glib shift in variables in a discussion of the entropy of a. gaseous mixture (p. 143 ff), fmm volume to total pnssure to partial (Continued
& page
AS96)
